Guides / 03—08
Read grain direction and usable width
A cutting calculation works only when the pattern may be oriented across the available fabric width.
Identify the fabric edges
Woven fabric usually has two lengthwise selvage edges. The direction parallel to them is the lengthwise grain. The bolt label states a nominal width, but usable width may be smaller because of selvages, defects or the chosen edge finish.
Follow the pattern direction
Grainline marks place pieces as designed. Rotating a piece 90 degrees may save fabric in arithmetic but can change drape, print direction or stretch. This site's panel calculator lays the cut width across the fabric width; use it only when that orientation matches your pattern.
Measure usable width
Measure actual fabric width after preparation and subtract the edges you will not use. Enter that usable width in the tool. With one-way prints, pile or nap, align every panel in the same direction and allow extra fabric beyond the tool's result.